[Code of Federal Regulations] [Title 46, Volume 2] [Revised as of October 1, 2004] From the U.S. Government Printing Office via GPO Access [CITE: 46CFR64.17] [Page 319] TITLE 46--SHIPPING CHAPTER I--COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PART 64_MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS--Table of Contents Subpart B_Standards for an MPT Sec. 64.17 Minimum tank thickness. (a) Except as allowed in paragraph (b) of this section, a tank with a diameter of-- (1) 6 feet or less must have a shell and head of \3/16\ inch thickness or more; or (2) More than 6 feet must have a shell and head of \1/4\ inch thickness or more. (b) If the tank has additional framework to guard against accidental puncturing of the tank, the shell and head thickness must be \1/8\ inch or more.